<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./vue.min.js"></script>
</head>
<body>
    <div id="app"> 
        <input v-model.number="price" type="text">
        <h3>{{price}}</h3>
        <p>{{newPrice}}</p>
        <p>{{newPrice}}</p>
        <p>{{newPrice}}</p>
    </div>
    <script>
        new Vue({
            el:'#app',
            data:{
                price:100,
            },
            computed:{
                newPrice(){
                    return "$"+this.price.toFixed(2);
                }
            }
        })
    </script>
</body>
</html>